Wireless communication devices, such as cellular telephones, cellular-enabled tablet computers, and other portable wireless devices with cellular communications capability can include wireless circuitry that can provide for communication in accordance with various wireless communication protocols. For example, cellular telephones, typically, include wireless personal area network (WPAN) radio frequency (RF) circuitry, such as Bluetooth® circuitry, and wireless local area network (WLAN) RF circuitry, such as Wi-Fi circuitry, to supplement cellular RF circuitry. Besides wireless communication capabilities, the WLAN RF circuitry and/or WPAN RF circuitry can provide, indirectly, a capability for a wireless communication device to estimate its location, e.g., a set of geospatial coordinates, using information based on RF signals received from one or more WLAN/WPAN access points (APs). (The use of the term “access point” or AP herein generally refers to a central wireless communication device that acts as a hub for a wireless network to interconnect multiple wireless communication devices. The AP can include a WLAN AP and/or a “master” WPAN device, which can be referred herein to informally as a WPAN AP.) The wireless communication device can be configured to use WLAN/WPAN AP information to supplement and/or to use in lieu of global positioning system (GPS) or global navigation satellite system (GNSS) information when estimating the location of the wireless communication device. When the wireless communication device operates indoors or in other locations in which GPS/GNSS signals can be attenuated or unavailable, the WLAN/WPAN AP information can be used to assist with estimating the location of the wireless communication device.
Multiple standards organizations define methods for location estimation, also referred to herein as positioning determination, for wireless communication devices, including the Third Generation Partnership Project (3GPP), which defines and publishes wireless communication protocols such as versions of Global System for Mobile Communications (GSM), Universal Mobile Telecommunications Services (UMTS), Long Term Evolution (LTE), and Long Term Evolution Advanced (LTE-A), the Open Mobile Alliance (OMA), which defines and publishes open standards for the mobile phone industry that apply across multiple cellular network technologies, and the Institute of Electrical and Electronics Engineers (IEEE), which standardizes wireless local area network (WLAN) communication protocols, such as the 802.11 family of standards. Each of the standards organizations can publish information about location/positioning aspects for wireless communication devices. Within 3GPP, standardized 3G and 4G wireless communication protocols, such as UMTS and LTE/LTE-A, include signaling layers, such as the radio resource control (RRC) layer at the control plane and the radio resources location services protocol (RRLP) at the user plane. The 4G wireless communication protocols such as LTE/LTE-A include an LTE positioning protocol (LPP) at the control plane and the secure user plan location (SUPL) at the user plane. Furthermore, the OMA has defined LPP container extensions (LPPe) to support newer technologies, e.g., improved assisted GNSS (A-GNSS), observed time difference of arrival (OTDOA), and use of WLAN at the control plane, and SUPL3.0 at the user plane. Additionally, the IEEE committee generates an 802.11v wireless network management protocol and an 802.11mc communication protocol, which will be published forthwith as the 802.11-2015 wireless communication protocol.
Regulatory bodies, such as the Federal Communications Commission (FCC), may require that emergency services, such as “911”, have access to the location of a wireless communication device, and, for “enhanced 911” (E911) services, may require that the availability of location estimation of wireless communication devices extend to indoor locations (or other locations in which GPS/GNSS can be inaccurate or unavailable). The FCC may require that 67% of wireless communication device connections be locatable for E911 purposes within an accuracy of 50 meters and that 95% of such connections be locatable within an accuracy of 150 meters. For “next generation 911” (NG911) services, to be introduced within the next five years, the FCC may recommend that 80% of connected wireless communication device be locatable within an accuracy of 50 meters for a horizontal (latitude/longitude) direction and within an accuracy of 3 meters for a vertical (altitude) direction. Current wireless communication devices, using limited GPS/GNSS information, can achieve an accuracy of only approximately 250 to 500 meters today.
As such, there exists a need for solutions that provide methods and apparatuses for assisting indoor location estimation by a wireless communication device using additional information, such as based on information about and/or measurements obtained from WLAN/WPAN APs and barometric sensors included in the wireless communication device. In this regard, it would be beneficial to provide for methods and apparatus that leverage WLAN/WPAN AP mappings and barometric sensor measurements to replace or supplement GPS/GNSS information used for estimating the location of a wireless communication device, particularly when connected to a wireless cellular network for emergency services access and when the wireless communication device operates in an indoor location, at which GPS/GNSS information may be limited or unavailable.